var exec = require('child_process').exec;
function puts(error, stdout, stderr) {
    if (error) return console.log('error\n', error);
    if (stderr) return console.log('stderr\n', stderr);
    if (stdout) return console.log('stdout\n', stdout);
}
exec("ls -la",puts);
// exec("who",puts);
// exec("mount",puts);